How to Make a Command Block Machine in No Mods Easy Command

A command block is a block that can execute commands. Because it cannot be obtained or edited in Survival mode without cheats, it is primarily used on multiplayer servers, in Creative worlds, and custom maps.

An impulse command block is the default block type, it executes only once when activated.

A chain command block executes every time when triggered.

A repeating command block executes every game tick as long as it is activated.

Obtaining [ ]

Command blocks are not available in the Creative inventory. It can either be obtained by using the pick block control, or by using various commands, such as /give @s minecraft:command_block, or /setblock ~ ~ ~ command_block.

Just like other blocks that can store NBT data, using pick block + CTRL copies the command and options inside the command block. This allows it to be placed elsewhere without having to re-enter the data inside.

Command blocks are not flammable, and have the same blast resistance as bedrock. Command blocks, structure blocks, and jigsaw blocks cannot be mined in Survival.

Command blocks cannot be placed by a non-operator player.

Usage [ ]

A command block can execute commands when activated by redstone power. It always has permissions of 2 level‌^{[ Java Edition only ]}/1 level‌^{[ Bedrock Edition only ]}, so it can be used to allow a specific use of a command by players who can't use that command in general (for example, allowing anyone to obtain a specific item with /give without allowing everyone to /give themselves whatever they want).

A command block has an orientation that determines the chain command block to activate, and the blocks to be checked to see if a command block in "Conditional" mode executes.

To execute the command, in Java Edition in multiplayer enable-command-block in the server.properties file must be set to true (default is false); in Bedrock Edition "Command Blocks Enabled" in options must be enabled.

Modification [ ]

Java Edition command block GUI.

To enter command or modify the command block, use the Use Item control on the command block to open the command block GUI (graphical user interface). The GUI opens only if the player is in Creative mode, and has the proper permissions. That means, in singleplayer, "Allow Cheats"‌^{[ JE only ]} or "Activate Cheats"‌^{[ BE only ]} in options must be enabled. In multiplayer, Gui can be opened only by operators in Creative mode, and in Java Edition op-permission-level in the server.properties file must be set to 2 or above (default is 4).

In Java Edition to enter command or modify the command block, enable-command-block in the server.properties file must be set to true (default is false).

Bedrock edition command block GUI.

In Java Edition, opening the GUI in singleplayer pauses the game.

Console Command‌^{[ JE only ]}/Command Input‌^{[ BE only ]}

Commands can be entered in the top text pane. The text limit for commands in a command block is 32,500 characters, but the text pane can show only a small portion of this amount at a time.

Commands in a command block do not need to be prefixed with the forward-slash (/) as they do in the chat window, but doing so still works.

Press Tab ↹ to complete words or cycle through options.

In Bedrock Edition, below the console command text pane are some reminder tips about how to use target selectors.

Previous Output

The bottom text pane displays the output message (success or failure) of the last executed command (it is blank‌^{[ JE only ]} or " - "‌^{[ BE only ]} initially). Its text is not editable.

A button to the right of the Previous Output text pane‌^{[ JE only ]} or the left of the "Previous Output"‌^{[ BE only ]} specifies whether the last output should be stored and displayed. It is O‌^{[ JE only ]}/enabled‌^{[ BE only ]} when the output text should be stored and X‌^{[ JE only ]}/disabled‌^{[ BE only ]} when the output text should not be stored. For worlds with many command blocks, especially command blocks running on fast clocks, not storing the output text can reduce memory and storage requirements.

If gamerule sendCommandFeedback is true (the default), default to O‌^{[ JE only ]}/enabled‌^{[ BE only ]}. Otherwise defaults to X‌^{[ JE only ]}/disabled‌^{[ BE only ]}.

Block Type

Left: "Impulse" block type.
Middle: "Chain" block type.
Right: "Repeating" block type.
Top: "Unconditional" mode.
Bottom: "Conditional" mode.

Click the "Impulse/Chain/Repeat"‌^{[ JE only ]}/"Block Type"‌^{[ BE only ]} button to change the command block's type. The default state is "Impulse", but non-default command blocks can be obtained and placed. The command block also changes color when changing its command block type:

• "Impulse" command blocks are orange. They execute once every time they are activated.
• "Chain" command blocks are green. They execute once every time they are triggered if they have been activated.
• "Repeat" command blocks are purple. They execute their commands once every one game tick (or more‌^{[ BE only ]}) as long as they are activated.

Condition

Click the "Conditional/Unconditional"‌^{[ JE only ]}/"Condition"‌^{[ BE only ]} button to change the command block's conditional behavior:

• "Conditional": A command block in conditional mode executes its command only when the command block behind it has executed successfully ("Success count" is greater than 0).
• "Unconditional" (default): A command block in unconditional mode executes its command even if there's a command block behind it that didn't execute its command successfully.

"Behind it" in the sense of opposite to the direction the command block is facing, regardless of chain direction or even if chaining is occurring.

Redstone

Click the "Always Active/Needs Redstone"‌^{[ JE only ]}/"Redstone"‌^{[ BE only ]} button to change the command block's activation requirements:

• "Needs Redstone" (the default for impulse and repeat command blocks): A command block in the "Needs Redstone" setting can be activated only with redstone.
• "Always Active" (the default for chain command blocks): The command block is activated when set to "Always Active". Then it is always active even without redstone activation.

Execute on First Tick‌^{[ BE only ]}

Specifies whether a repeat command block executes its command as soon as it is activated. If it's disabled, executes the first time after the delay from the time when it is activated.

Delay in Ticks‌^{[ BE only ]}

For impulse or chain command block, specifies how many game ticks it delays before executing a command after it is activated or triggered.

For repeat command block, specifies how many game ticks it delays to execute again.

Note that for impulse or repeat command block, 0 and 1 work the same; the game takes 0 as 1. However, For chain command block, 0 and 1 are different.

Hover Note‌^{[ BE only ]}

Specifies the name of the command block, which can be seen when you point to the block. It is also used for message commands. If the command block had been named in an anvil before placement, that name is used as well. If it is empty, defaults to !.

Done

In Java Edition, click the "Done" button or ↵ Enter to save the command and leave the command block GUI.

In Bedrock Edition, close the GUI to save the command and changes.

Cancel

Click the "Cancel" button or Esc‌^{[ JE only ]}to leave the command block GUI without saving any changes.

Activation [ ]

Command blocks are redstone mechanisms and can be activated by:

• An adjacent active power component: for example, a lever, a block of redstone, a daylight sensor, a button etc.
• An adjacent powered block (for example, an opaque block with an active redstone torch under it)
• A powered redstone comparator or redstone repeater facing the mechanism component
• Powered redstone dust configured to point at the command block (or on top of it) or directionless; a command block is not activated by adjacent powered redstone dust that is configured to point away from it.

A command block can also be activated by setting it to "Always Active" mode.

When activated, a command block executes its command, depending on the command block's type:

• An impulse command block executes its command once.
• A chain command block does not execute its command until it is triggered.
• A repeat command block executes its command once every one game tick (or more‌^{[ BE only ]}) until no longer activated.

Execution [ ]

An impulse command block, when it is activated, checks whether the command block behind it has executed successfully (if in conditional mode). After the delay of 1 game tick (or more‌^{[ BE only ]}), if the condition is met before the delay (if in "Conditional" mode), it executes its command once and triggers the chain command block it is pointing to.

A repeat command block, when it is activated, after 1 game tick (always 1 no matter how many "Delay in Ticks" is), checks whether the command block behind it has executed successfully (if in conditional mode). If the condition is met, and if "Execute on First Tick‌" is enabled in Bedrock Edition, it executes its command once and triggers the chain command block it is pointing to. If it is still activated, it then checks, executes, and triggers the chain command block again after 1 game tick (or more‌^{[ BE only ]}).

When executing a command, it also updates its success count: If in "Conditional" mode, if the command block behind it didn't execute successfully, it sets its success count to 0. Otherwise, it sets it to the success count of the command.

Also:

• When an impulse or repeat command block in "Needs Redstone" mode with a command is placed or is cloned by a command to a powered location, the new command block executes its command only if it hasn't been activated with redstone. In Java Edition, it also needs a block update to execute its command.
• When an impulse or repeat command block in "Always Active" mode with a command is placed or is cloned by a command to a powered location, the new command block executes its command only if it hasn't been activated with redstone.
• When an impulse or chain command block is set to "Repeat", if it has been activated, checks whether the command block behind it has executed successfully (if in conditional mode). After 1 game tick (always 1 no matter how many "Delay in Ticks" is), if the condition is met, it executes its command once and triggers the chain command block it is pointing to. Then it checks, executes, and triggers the chain command block again after 1 game tick (or more‌^{[ BE only ]}).

Trigger and chaining [ ]

If any command block having executed its command (whether successfully or unsuccessfully) faces a chain command block, it triggers the chain command block to also attempt execution.

When a chain command block is triggered,

• If it has been activated,
  • It checks whether it is in "Conditional" mode and the command block behind it hasn't executed successfully (Behind in the sense of the direction it is facing, not in the sense of which command block chained to it),
    • If true, it triggers another chain command block it is facing, without executing the command.
    • If false, it checks whether it has been already executed in this game tick. If false, it executes the command and triggers another chain command block it is facing. If true, it does nothing. That means that chained execution cannot be passed to a command block that has already executed in that game tick (loops execute only once).
• If it has not been activated, it triggers the chain command block it is facing to attempt execution.

Chained command blocks execute simultaneously in the same game tick in the order they are chained.

In Bedrock Edition, it can also delay before executing commands if "Delay in Ticks" is not 0:

When it is triggered,

• If it has been activated, the chain command block checks whether the command block behind it has executed successfully (if in conditional mode), then it delays.
  • After a delay, if the condition is met before the delay (if in "Conditional" mode), it executes its command once and triggers the chain command block it is pointing to no matter whether the condition met.
• If it has not been activated, it triggers (without delay) the chain command block it is facing to attempt execution.

In Java Edition, it can execute multiple times in the same game tick if "UpdateLastExecution" is set to false. In this case, it does not check whether it has already executed in this game tick.

If the chain command block has been activated when triggered, it also updates its success count: If in "Conditional" mode, if the command block behind it didn't execute successfully, it sets its success count to 0. Otherwise, it sets it to the success count of the command.

Output [ ]

When activated, a command block can produce multiple types of output:

Success count [ ]

A command block can power a redstone comparator facing away from it (possibly separated by a block) with signal strength specific to the success count. Success count is an integer between 0 to 2,147,483,647 (inclusive).

The signal strength always reflects the last command executed, even after the command block is deactivated.

In Java Edition, success count is usually 0 or 1, except for /function and /execute.

In Bedrock Edition, success count is an integer related to the command (e.g., the number of players affected by the command, the number of blocks that were altered, the value returned by the command, etc.)

In Java Edition, leaving the command block GUI by clicking "Done" or pressing ↵ Enter resets the success count to 0, regardless of whether changes were made in the GUI. In Bedrock Edition, leaving the GUI with changes resets the success count to 0.

Message [ ]

The output message describes the success or failure of the executed command, and may be written to multiple destinations:

Previous Output: The output message is always written to the "Previous Output" text pane of the command block GUI.

Chat: The output message is written to the chat text in singleplayer mode, or broadcast to all other ops in multiplayer mode, unless it has been suppressed with /gamerule commandBlockOutput false. Some commands may write additional text to the chat as their normal function, which won't be suppressed (for example, the /say command writes a message to the chat of all players), separate from the output message. Chat messages that would usually be prefaced by a player's name (such as from the /me, /say and /tell commands) use @ ‌^{[ Java Edition only ]} / ! ‌^{[ Bedrock Edition only ]} as the player name. If the command block had been named in an anvil before placement, that name is used instead. In Bedrock Edition, it can also modified in the GUI.

Logs: The output message is written to multiplayer server logs unless it has been suppressed with /gamerule logAdminCommands false.

Notes [ ]

Command blocks execute commands with OP level 2. The following commands cannot be used in a command block: /ban, /banlist, /ban-ip, /debug, /deop, /kick‌^{[ JE only ]}, /op, /pardon, /pardon-ip, /publish, /reload‌^{[ BE only ]}, /save-all, /save-off, /save-on, /stop, and /whitelist (i.e., /debug, /publish, and all of the multiplayer-only commands except /list).

Easter eggs [ ]

Running "Searge" (case insensitive) as the command in the command block without a preceding "/" will set the previous output to "#itzlipofutzli". Its success count is 1.

Piston interactivity [ ]

Command blocks cannot be pushed by pistons. They also cannot be pushed or pulled by sticky pistons.

Sounds [ ]

Java Edition:

Sound	Subtitles	Source	Description	Resource location	Translation key	Volume	Pitch	Attenuation distance
	Block broken	Blocks	Once the block has broken	block.metal.break	subtitles.block.generic.break	1.0	1.2	16
	None [sound 1]	Blocks	Falling on the block with fall damage	block.metal.fall	None [sound 1]	0.5	1.25	16
	Block breaking	Blocks	While the block is in the process of being broken	block.metal.hit	subtitles.block.generic.hit	0.25	0.75	16
	Block placed	Blocks	When the block is placed	block.metal.place	subtitles.block.generic.place	1.0	1.2	16
	Footsteps	Blocks	Walking on the block	block.metal.step	subtitles.block.generic.footsteps	0.15	1.5	16

1. ↑ ^{a b} MC-177082

Bedrock Edition: ^{[ needs in-game testing ]}

Sound	Source	Description	Resource location	Volume	Pitch
?	?	Once the block has broken	dig.metal	?	1.2
?	?	Falling on the block with fall damage	fall.metal	?	?
?	?	While the block is in the process of being broken	hit.metal	?	0.75
?	?	Jumping from the block	jump.metal	?	?
?	?	Falling on the block without fall damage	land.metal	?	?
?	?	Walking on the block	step.metal	?	?
?	?	When the block is placed	use.metal	?	1.2

Data values [ ]

ID [ ]

Java Edition:

Name	Identifier	Form	Block tags	Translation key
Command Block	command_block	Block & Item	dragon_immune wither_immune	block.minecraft.command_block
Chain Command Block	chain_command_block	Block & Item	dragon_immune wither_immune	block.minecraft.chain_command_block
Repeating Command Block	repeating_command_block	Block & Item	dragon_immune wither_immune	block.minecraft.repeating_command_block

Name	Identifier
Block entity	command_block

Bedrock Edition:

Name	Identifier	Numeric ID	Form	Item ID[i 1]	Translation key
Command Block	command_block	137	Block & Giveable Item[i 2]	Identical[i 3]	tile.command_block.name
Chain Command Block	chain_command_block	189	Block & Giveable Item[i 2]	Identical[i 3]	tile.chain_command_block.name
Repeating Command Block	repeating_command_block	188	Block & Giveable Item[i 2]	Identical[i 3]	tile.repeating_command_block.name

1. ↑ ID of block's direct item form, which is used in savegame files and addons.
2. ↑ ^{a b c} Available with /give command.
3. ↑ ^{a b c} The block's direct item form has the same id with the block.

Name	Savegame ID
Block entity	CommandBlock

Block states [ ]

Java Edition:

Name	Default value	Allowed values	Description
conditional	false	false true	True if the command block is in conditional mode.
facing	north	down east north south up west	The direction the command block is pointing.

Bedrock Edition:

Name	Metadata Bits	Default value	Allowed values	Values for Metadata Bits	Description
conditional_bit	0x8	false	false true	0 1	True if the command block is in conditional mode.
facing_direction	0x1 0x2 0x4	0	0 1 2 3 4 5	0 1 2 3 4 5	The direction the command block is pointing. 0: facing down 1: facing up 2: facing north 3: facing south 4: facing west 5: facing east

Block data [ ]

A command block has a block entity associated with it that holds additional data about the block.

Java Edition:

• Block entity data
  •  auto: 1 or 0 (true/false) - Allows to activate the command without the requirement of a redstone signal.
  •  Command: The command to issue to the server.
  •  conditionMet: 1 or 0 (true/false) - Indicates whether a conditional command block had its condition met when last activated. True if not a conditional command block.
  •  CustomName: Optional. The name JSON text component of this command block, replacing the usual '@' when using commands such as /say and /tell.
  •  LastExecution: stores the tick a chain command block was last executed in.
  •  LastOutput: The last line of output generated by the command block. Still stored even if the gamerule commandBlockOutput is false. Appears in the GUI of the block when right-clicked, and includes a timestamp of when the output was produced.
  •  powered: 1 or 0 (true/false) - States whether or not the command block is powered by redstone or not.
  •  SuccessCount: Represents the strength of the analog signal output by redstone comparators attached to this command block.
  •  TrackOutput: 1 or 0 (true/false) - Determines whether the LastOutput is stored. Can be toggled in the GUI by clicking a button near the "Previous Output" textbox. Caption on the button indicates current state: "O" if true, "X" if false.
  •  UpdateLastExecution: 1 or 0 (true/false) - Defaults to true. If set to false, loops can be created where the same command block can run multiple times in one tick.

Bedrock Edition:

See Bedrock Edition level format/Block entity format.

History [ ]

Java Edition
July 27, 2012					Jeb began tweeting of a new block he had created to start expanding Adventure mode. He began posting pictures, ideas and hints of what the block can do.
July 31, 2012					During Notch's AMA on Reddit, he hinted the block may be in Java Edition 1.4.
1.4.2		12w32a			Added command blocks.
1.5		13w03a			Command block success can now power a redstone comparator.
		13w04a			Command blocks renamed with an anvil now use their name instead of @ in the chat.
		13w10a			Pressing Esc in a command block will exit its GUI.
1.6.1		13w19a			Command blocks are no longer mineable in Survival.
					Command blocks are no longer damaged by explosions, except by blue wither skulls.
1.7.2		13w37a			A bar that shows the previous output of command blocks has been added.
					The character limit when inserting a command in a command block has been increased from 256 to 16,369. Using a third-party editor allows the player to reach 32,767 characters.
1.8		14w07a			Dispensers now place command blocks, instead of shooting them out.
		14w20a			The in-game character limit of 16,369 has been removed, allowing access to the full 32,767 characters.
		14w27a			Added CommandStats NBT tag to command blocks.
1.8.6					Dispensers no longer place command blocks.[1]
1.9		15w33a			The character limit for command blocks is now 32,500 instead of 32,767.
		15w34a			Added the chain command block and the repeating command block.
					Added block facing for command blocks.
					The texture of command blocks has been changed.
		15w34b			Added Conditional mode within command blocks.
					Added tab completion support within command blocks.
		15w35a			The textures of all three command blocks have been changed.
					When command blocks are set to conditional, the back of the arrow texture is now curved.
					Added Always active and needs redstone options for command blocks.
					Added auto NBT tag to control redstone options within command blocks.
		15w36a			Players are now unable to use commands, such as /give, within command blocks.
					Players, who are unable to use commands, can no longer place command blocks.
		15w36d			Each command block type now appears with different colors on maps.
		16w02a			Running /help in a command block now randomly uses one of various different humorous phrases as the previous output.
		16w04a			Running "Searge" as the command in the command block without a preceding "/" now sets the previous output to "#itzlipofutzli".
1.11		16w32a			The block entity ID has been changed from Control to command_block.
1.12		17w16a			Chains of command blocks no longer schedule their commands to be run in the next tick. Instead, they now execute all in the same tick they are read. This allows later blocks in a chain to be modified via earlier blocks, allowing techniques like branching and looping, all in the same tick.
					Added maxCommandChainLength game rule to control the max length of such a chain.
		17w17a			Added UpdateLastExecution and LastExecution NBT tags, which control the tracking of which tick a chain command block was last executed in.
		pre6			Tab-completing command names in command blocks no longer add a / prefix.
1.13		17w47a			Prior to The Flattening, the numeral IDs for the command block, repeating command block, and chain command block were 137, 210, and 211, respectively.
		pre1			The player can now tab-complete in command blocks again.
1.14		18w43a			The textures of command blocks have been changed.
		18w47b			The textures of impulse and repeating command blocks have been changed.
Pocket Edition
1.0.5		alpha 1.0.5.0			Added all types of command blocks.
Bedrock Edition
1.8.0		beta 1.8.0.8			Command blocks now have a default name of ! instead of @.
1.10.0		beta 1.10.0.3			The textures of command blocks have been changed.
1.12.0		beta 1.12.0.2			Tab-complete has been added to command blocks.
					Added a delay option to command blocks, which allows a delay to be added to a redstone tick delay field.
Legacy Console Edition
TU19	CU7	1.12	Patch 1		Added command blocks.
					Command blocks do not have any functionality and can be obtained only with mods.

Gallery [ ]

• 

  The first image released by Mojang of the command block.

• 

  The second image released by Mojang showing the block giving glass to the player.

Issues [ ]

Issues relating to "Command Block" are maintained on the bug tracker. Report issues there.

References [ ]

1. ↑ https://bugs.mojang.com/browse/MC-80671?focusedCommentId=228546&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-228546

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Source: https://minecraft.fandom.com/wiki/Command_Block

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